Tamiya’s wall-hugging mouse is a fun and easy-to-build kit that’s great for new robot enthusiasts, and it can serve as a unique, hackable robot chassis for more advanced users. The mouse has no digital electronics, and a simple wire bumper along its side directs current to one of two motors to keep the mouse moving along the wall. The mouse features a thin plastic shell and runs on one C battery.

The wall hugging mouse squiggles along a wall in a zig-zag manner. When the bump sensor makes contact with the wall, a switch directs power to the left motor, which moves the mouse to the right and away from the wall. When the bump sensor loses contact, the switch flips directs power to the right motor, moving the mouse to the left and towards the wall again. This simple behavior allows the robot to follow almost any vertical surface on its left.

The electronics—motors, power switch, and bumper switch—are pre-assembled (no soldering is required). The thin, clear body can be painted from the inside for an attractive finish that won’t easily scratch. To assemble the mouse you will need a screwdriver, diagonal cutters, and long nose pliers; Tamiya also recommends a modeling knife for removing excess plastic.

For a similar kit, consider Tamiya’s wall-hugging ladybug; the ladybug comes with a harder plastic shell, uses a AA battery instead of a C, and is a bit easier to assemble. If you are looking for something that will be a bit more of an assembly challenge, check out Tamiya’s Robocraft Series of small mechanical animals that crawl, jump, or run with the use of gearboxes similar to the ones in the Tamiya gearbox kits.

Because this kit has two independent motors for differential drive, it can also serve as a base for your own project. There is ample space for adding your own electronics, and you can readily modify the plastic base.

Note: The wall-hugging mouse is a kit; assembly is required. One C battery is required but not included.